Gas-solids reactors, which often constitute critical steps of energy and chemical conversion processes, are in desperate need of new design methods to increase their efficiency and reliability, as they are poorly understood and difficult to improve upon. Computational Gas-Solids Flows and Reacting Systems: Theory, Methods and Practice addresses the need for a comprehensive book on computational gas-solids flow to aid researchers, graduate students, and practicing engineers in this rapidly expanding area. This unique book provides a full exploration of the theory, numerical methods, and practices associated with this emerging area, including hydrodynamic equations, quadrature-based moment methods, and direct numerical simulation.